Random access method, evolved node b, and terminal equipment

ABSTRACT

A random access method, an evolved Node B (eNB), and a terminal equipment are provided. The method includes: determining target component carriers to which a User Equipment (UE) is to be handed over, and notifying the UE of information about the target component carriers through a source eNB; and after receiving a dedicated random access preamble sent by the UE, sending a random access response message on at least one component carrier in the target component carriers. The terminal equipment includes: a handover command receiving unit, a sending unit, and a random response receiving unit. Therefore, in a random access procedure of cell handover, the eNB is capable of determining downlink component carriers that a UE monitors, thereby increasing utilization rate of downlink resources.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.13/253,709, filed on Oct. 5, 2011, which is a continuation ofInternational Application No. PCT/CN2009/071200, filed on Apr. 9, 2009,which is hereby incorporated by reference in its entirety.

TECHNICAL FIELD

The present invention relates to the field of communicationtechnologies, and in particular, to a random access method, an evolvedNode B (eNB), and a terminal equipment.

BACKGROUND

With the development of wireless communications technologies, in orderto satisfy requirements of the International Mobile TelecommunicationAdvanced (IMT-Advanced) and to support a peak data speed being up to 1G,a Long Term Evolution system currently uses a carrier aggregationtechnology as a method for expanding a system bandwidth. Carrieraggregation mainly aggregates multiple component carriers into onecarrier higher than 20 million hertz (M) to support high datatransmission speed.

Currently, an LTE or Long Term Evolution-Advanced (LTE-A) system needsto support asymmetric carrier aggregation. Generally, the number ofdownlink component carriers is greater than the number of uplinkcomponent carriers. For example, a downlink bandwidth of 80 millionhertz (MHz) includes four component carriers of 20 MHz. An uplinkbandwidth of 20 MHz includes one component carrier of 20 MHz.

In the current LTE system, in a handover process, a non-competitiveprocedure for a User Equipment (UE) to randomly access a target eNBincludes the following steps.

The UE sends a measurement report to a source eNB, and the source eNBselects a target eNB and a target cell for the UE according to thereceived measurement report or other radio resource information, thatis, the source eNB makes a handover decision. Then, the source eNB sendsa handover request message to the target eNB. After receiving thehandover request message, the target eNB executes admission control andfeeds back a handover request acknowledgement message to the source eNB.When receiving the handover request acknowledgement message, the sourceeNB sends a handover command message to the UE. After the UE receivesthe handover command message, if the UE receives a dedicated randomaccess preamble allocated by the target eNB to the UE, the UE sends arandom access request message to the target eNB through the dedicatedrandom access preamble, that is, the UE executes non-competitive randomaccess; if the UE does not receive the dedicated random access preambleallocated by the target eNB to the UE, the UE executes competitiverandom access. After receiving the random access preamble sent by theUE, the target eNB sends a random access response message to the UE.

However, the inventor of the present invention finds that, in theforegoing process, when the target eNB includes multiple componentcarriers, after the target eNB receives the random access requestmessage, the target eNB cannot determine the component carrier which theUE is monitoring, in order to enable the UE to receive the random accessresponse message, the target eNB needs to send the random accessresponse message on all component carriers, thereby resulting in a wasteof downlink resources.

SUMMARY

Embodiments of the present invention provide a random access method, aneNB, and a terminal equipment, so that in a random access procedure ofcell handover, the eNB is capable of determining a downlink componentcarrier that a UE monitors, thereby increasing utilization rate ofdownlink resources.

In order to solve the above technical problems, an embodiment of thepresent invention provides a random access method, which includes:

-   -   determining target component carriers to which a User Equipment        (UE) is to be handed over, and notifying the UE of information        about the target component carriers through a source eNB; and    -   after receiving a dedicated random access preamble sent by the        UE, sending a random access response message on at least one        component carrier in the target component carriers.

An embodiment of the present invention further provides a random accessmethod, which includes:

-   -   receiving a handover command sent by a source eNB, where the        handover command includes information about target component        carriers configured by a target eNB or selected by the source        eNB, and the target component carriers are carriers to which a        User Equipment (UE) is to be handed over; and    -   after sending a dedicated random access preamble to the target        eNB, receiving a random access response message on a downlink        target carrier in the target component carriers.

Accordingly, an embodiment of the present invention further provides aneNB, which includes:

-   -   a determination unit, adapted to determine target component        carriers to which a UE is to be handed over;    -   a notification unit, adapted to notify the UE of information        about the target component carriers through a source eNB; and    -   a sending unit, adapted to send a random access response message        on at least one component carrier in the target component        carriers after a dedicated random access preamble sent by the UE        is received.

An embodiment of the present invention provides a terminal equipment,which includes:

-   -   a handover command receiving unit, adapted to receive a handover        command sent by a source eNB, where the handover command        includes information about target component carriers configured        by a target eNB or selected by the source eNB, and the target        component carriers are carriers to which a UE is to be handed        over;    -   a sending unit, adapted to send a dedicated random access        preamble to the target eNB after the handover command receiving        unit receives the handover command; and    -   a random response receiving unit, adapted to receive a random        access response message on a downlink component carrier in the        target component carriers configured for the UE after the        sending unit sends the dedicated random access preamble.

It can be known from the foregoing solutions that, in the embodiments ofthe present invention, the UE learns from the handover command thetarget component carriers for the target eNB to send the random accessresponse message after receiving the handover command sent by the sourceeNB, so as to receive, on the downlink target component carrier in thetarget component carriers, the random access response message sent bythe target eNB, thereby reducing power consumption of the UE, andmeanwhile, the target eNB further learns the component carriers forsending the random access response message after receiving the dedicatedrandom access preamble sent by the UE, thereby increasing theutilization rate of the downlink resources.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a flow chart of a random access method according to anembodiment of the present invention;

FIG. 2 is a flow chart of another random access method according to anembodiment of the present invention;

FIG. 3A and FIG. 3B are a specific flow chart of a random access methodaccording to Embodiment 1 of the present invention;

FIG. 4A and FIG. 4B are a specific flow chart of a random access methodaccording to Embodiment 2 of the present invention;

FIG. 5 is a flow chart of a component carrier handover method accordingto an embodiment of the present invention;

FIG. 6 is a flow chart of another component carrier handover methodaccording to an embodiment of the present invention;

FIG. 7 is a specific flow chart of a component carrier handover methodaccording to Embodiment 4 of the present invention;

FIG. 8 is a schematic structure diagram of an eNB according to anembodiment of the present invention;

FIG. 9 is a schematic structure diagram of a terminal equipmentaccording to an embodiment of the present invention;

FIG. 10 is a schematic structure diagram of another terminal equipmentaccording to an embodiment of the present invention; and

FIG. 11 is a schematic structure diagram of another eNB according to anembodiment of the present invention.

DETAILED DESCRIPTION

Exemplary embodiments of the present invention will be described indetail in the following with reference to the accompanying drawings.

Referring to FIG. 1, FIG. 1 is a flow chart of a random access methodaccording to an embodiment of the present invention. The method includesthe following steps.

Step 101: A target eNB determines target component carriers to which aUE is to be handed over, and notifies the UE of information about thetarget component carriers through a source eNB.

Step 102: After receiving a dedicated random access preamble sent by theUE, the target eNB sends a random access response message on at leastone component carrier in the target component carriers.

Step 101 specifically includes the following steps.

After receiving a handover request message sent by the source eNB, thetarget eNB determines the information about the target componentcarriers to which the UE is to be handed over according to the handoverrequest message, and notifies the source eNB of the information aboutthe target component carriers through a handover request acknowledgementmessage, and the source eNB sends the target component carriers to theUE through a handover command.

In an exemplary embodiment, the target eNB receives the handover requestmessage sent by the source eNB, where the handover request messageincludes the UE's capability information about the target componentcarriers being supported; configures the target component carriers towhich the UE is to be handed over according to the handover requestmessage; and then sends the handover request acknowledgement message tothe source eNB, where the handover request acknowledgement messageincludes information about the configured target component carriers, towhich the UE is to be handed over.

In another exemplary embodiment, the target eNB receives the handoverrequest message sent by the source eNB, where the handover requestmessage includes the UE's capability information about the targetcomponent carriers being supported and the information of the targetcomponent carriers selected by the source eNB, and the target componentcarriers configured are the carriers to which the UE is to be handedover. Then, the target eNB determines whether to allow the source eNB toselect the target component carriers to which the UE is to be handedover; if the target eNB allows the source eNB to select the targetcomponent carriers to which the UE is to be handed over, the target eNBsends the handover request acknowledgement message to the source eNB,where the handover request acknowledgement message includesacknowledgement information of the target component carriers selected bythe source eNB, or information about the target component carriersselected by the source eNB, and the target component carriers are thecarriers to which the UE is to be handed over; and if the target eNBdoes not allow the source eNB to select the target component carriers towhich the UE is to be handed over, the target eNB configures the targetcomponent carriers to which the UE is to be handed over, and sends thehandover request acknowledgement message to the source eNB, where thehandover request acknowledgement message includes the information aboutthe target component carriers configured, to which the UE is to behanded over.

In this embodiment, after sending the random access response message,the method may further include the following steps.

After a handover acknowledgement message sent by the UE is received, newuplink and/or downlink component carriers or new component carrier pairsare allocated to the UE.

The sending, by the source eNB, the target component carriers to the UEthrough the handover command specifically includes: after receiving thehandover acknowledgement message sent by the target eNB, sending, by thesource eNB, the handover command to the UE, where the handover commandincludes: the information about the target component carriers configuredby the target eNB, or the information about the target componentcarriers selected by the source eNB, and the target component carriersare the carriers to which the UE is to be handed over.

The handover request acknowledgement message may further includebandwidths of the target component carriers configured by the targeteNB, and the target component carriers are the carriers to which the UEis to be handed over. The handover command may further includebandwidths of the target component carriers configured by the targeteNB, and the target component carriers are the carriers to which the UEis to be handed over, or bandwidths of the target component carriersselected by the source eNB, and the target component carriers are thecarriers to which the UE is to be handed over.

In the embodiment of the present invention, the target componentcarriers may include, but are not limited to, uplink and/or downlinktarget component carriers or target component carrier pairs selected bythe source eNB or the target eNB for the UE, or an uplink and/or adownlink component carrier or a component carrier pair used to executerandom access. The information about the target component carriers mayinclude, but is not limited to, frequency information, identifiers, orsequence numbers of the uplink and/or downlink target component carriersor the target component carrier pairs, or frequency information, anidentifier, or a sequence number of the uplink and/or downlink componentcarrier or the target component carrier pair used to execute the randomaccess.

Accordingly, an embodiment of the present invention further provides arandom access method. FIG. 2 is a flow chart of the random accessmethod. The method includes the following steps.

Step 201: A terminal equipment receives a handover command sent by asource eNB, where the handover command includes information about targetcomponent carriers configured by a target eNB, or information abouttarget component carriers selected by the source eNB, and the targetcomponent carriers are the carriers to which the UE is to be handedover.

Step 202: After sending a dedicated random access preamble to the targeteNB, the terminal equipment receives a random access response message ona downlink target carrier in the target component carriers configured,to which the UE is to be handed over, or on a downlink component carrierin the target component carriers selected, to which the UE is to behanded over.

After receiving the random access response message, the method mayfurther include: after sending a handover acknowledgement message to thetarget eNB, receiving new uplink and/or downlink target componentcarriers or new uplink and/or downlink target component carrier pairsallocated by the target eNB to the UE.

The method further includes: receiving a component carrier handovercommand sent by the target eNB, where the component carrier handovercommand includes information about component carriers or componentcarrier pairs re-selected, to which the UE is to be handed over; handingover the UE to the component carriers or the component carrier pairsre-selected; and transmitting data on the component carriers or thecomponent carrier pairs re-selected after handover.

The method further includes: when the component carrier handover commandsent by the target eNB is received, receiving a new timing advancecommand or new timing advance information sent by the target eNB. Thetransmitting the data on the component carriers or the component carrierpairs after handover further includes: transmitting the data on thecomponent carriers or the component carrier pairs after handover throughthe new timing advance command or the new timing advance information.

In this embodiment, the component carrier handover command furtherincludes a handover starting time of the component carrier or thecomponent carrier pair.

The information about the component carriers or the component carrierpairs includes: frequency information, identifiers, or sequence numberinformation of the component carriers or the component carrier pairs.

For the convenience of understanding by persons skilled in the art, aspecific embodiment is provided in the following for illustration.

FIG. 3A and FIG. 3B are a specific flow chart of a random access methodaccording to Embodiment 1 of the present invention. Referring to FIG. 3Aand FIG. 3B, the method specifically includes the following steps.

Step 301: A UE sends a measurement report to a source eNB.

Specifically, the measurement report may include signal qualityinformation of component carriers of neighbor eNBs, where the signalquality information is measured by the UE.

Step 302: After receiving the measurement report, the source eNB makes ahandover decision to select uplink and/or downlink target componentcarriers or target component carrier pairs for the UE.

After receiving the measurement report, the source eNB makes thehandover decision based on the measurement report and other radioresource information. Specifically, the source eNB may decide, accordingto component carriers being supported by the UE, the uplink and/ordownlink target component carriers or the target component carrier pairsused by the UE when the UE accesses a target eNB. That is, the sourceeNB selects the uplink and/or downlink target component carriers or thetarget component carrier pairs for the UE based on the measurementreport.

Step 303: The source eNB sends a handover request message to the targeteNB, where the handover request message includes the UE's capabilityinformation about the supported component carriers and information aboutthe target component carriers selected by the source eNB, and the targetcomponent carriers are the carriers to which the UE is to be handedover.

That is, the handover request message includes the UE's capabilityinformation about the target component carriers being supported and theinformation about the uplink and/or downlink target component carriersor the target component carrier pairs selected by the source eNB for theUE.

Step 304: After receiving the handover request message, the target eNBdetermines whether to allow the source eNB to select the uplink and/ordownlink target component carriers or the uplink and/or downlinkcomponent carrier pairs to which the UE is to be handed over; if thetarget eNB allows the source eNB to select the uplink and/or downlinktarget component carriers or the uplink and/or downlink componentcarrier pairs to which the UE is to be handed over, step 305 isexecuted; and if the target eNB does not allow the source eNB to selectthe uplink and/or downlink target component carriers or the uplinkand/or downlink component carrier pairs to which the UE is to be handedover, step 305′ and step 306 are executed.

Step 305: The target eNB sends a handover request acknowledgementmessage to the source eNB, where the handover request acknowledgementmessage includes acknowledgement information of the uplink and/ordownlink component carriers or the component carrier pairs selected bythe source eNB for the UE, or the handover request acknowledgementmessage includes the information about the uplink and/or downlink targetcomponent carriers or the target component carrier pairs selected by thesource eNB for the UE.

Step 305′: The target eNB configures new uplink and/or downlink targetcomponent carriers or target component carrier pairs for the UE.

Step 306: The target eNB sends the handover request acknowledgementmessage to the source eNB, where the handover request acknowledgementmessage includes: information about the new uplink and/or downlinktarget component carriers or target component carrier pairs configuredby the target eNB for the UE.

The target eNB may further include bandwidths of the new uplink and/ordownlink target component carriers or target component carrier pairsselected for the UE, where the bandwidths are included in the handoverrequest acknowledgement message. The embodiment of the present inventionis not limited thereto.

Step 307: The source eNB sends a handover command message to the UE.

If the target eNB accepts the uplink and/or downlink target componentcarriers or the target component carrier pairs selected by the sourceeNB for the UE, the handover command includes the information about theuplink and/or downlink target component carriers or the target componentcarrier pairs selected by the source eNB for the UE. The handovercommand may further include bandwidth information of the selected uplinkand/or downlink target component carriers or target component carrierpairs.

If the target eNB cannot allow the source eNB to select all or a part ofthe uplink and/or downlink target component carriers or the targetcomponent carrier pairs for the UE, the handover command includes theinformation about the uplink and/or downlink target component carriersor the target component carrier pairs selected by the target eNB for theUE. The handover command may further include the bandwidth informationof the selected uplink and/or downlink target component carriers ortarget component carrier pairs.

Step 308: After receiving the handover command, the UE sends a randomaccess preamble to the target eNB, where the handover command includesthe information about the uplink and/or downlink target componentcarriers or the target component carrier pairs selected for the UE. Thehandover command may further include the bandwidth information of theselected uplink and/or downlink target component carriers or targetcomponent carrier pairs.

That is, after the handover command is received, a process forsynchronizing with a target cell is executed to access the target cell.The UE monitors the uplink and/or downlink target component carriers orthe target component carrier pairs according to the information aboutthe allocated uplink and/or downlink target component carriers or targetcomponent carrier pairs, where the information is in the handovercommand.

Step 309: After receiving the preamble sent by the UE, the target eNBsends a random access response message to the UE on one target componentcarrier in the downlink target component carriers selected for the UE.

In this embodiment, the information about the target component carriersspecifically includes the uplink and/or downlink target componentcarriers or the target component carrier pairs selected by the sourceeNB for the UE, or frequency information, identifiers, or sequencenumbers of the uplink and/or downlink target component carriers or thetarget component carrier pairs, but the embodiment is not limitedthereto.

FIG. 4A and FIG. 4B are a specific flow chart of a random access methodaccording to Embodiment 2 of the present invention. The methodspecifically includes the following steps.

Step 401: A UE sends a measurement report to a source eNB. Specifically,the measurement report may include signal quality information ofcomponent carriers of neighbor eNBs, where the signal qualityinformation is measured by the UE.

Step 402: The source eNB makes a handover decision to select an uplinkand/or a downlink component carrier or target component carrier pair forthe UE to use when the UE executes a random access to a target eNB.

That is, the source eNB makes the handover decision based on themeasurement report sent by the UE and other radio resource information.That is, the source eNB may select, according to the component carriersbeing supported by the UE, the uplink and/or the downlink componentcarrier or the target component carrier pair for the UE to use when theUE executes the random access to the target eNB.

Step 403: The source eNB sends a handover request message to the targeteNB, where the handover request message includes the UE's capabilityinformation about the supported component carriers, and/or informationabout the component carriers or the target component carrier pairsselected by the source eNB for the UE to use when the UE executes therandom access to the target eNB.

Step 404: After receiving the handover request message, the target eNBdetermines whether to allow the source eNB to select the uplink and/orthe downlink component carrier or the component carrier pair used toexecute the random access for the UE; if the target eNB allows thesource eNB to select the uplink and/or downlink component carrier or thecomponent carrier pair used to execute the random access for the UE,step 405 is executed; and if the target eNB does not allow the sourceeNB to select the uplink and/or downlink component carrier or thecomponent carrier pair used to execute the random access for the UE,step 405′ and step 406 are executed.

Step 405: The target eNB sends a handover request acknowledgementmessage to the source eNB, where the handover request acknowledgementmessage includes acknowledgement information of the uplink and/ordownlink component carrier or the component carrier pair selected by thesource eNB for the UE to use when the UE executes the random access.Alternatively, the handover request acknowledgement message includesinformation about the uplink and/or downlink component carriers or thecomponent carrier pairs selected by the source eNB for the UE to usewhen the UE executes the random access to the target eNB.

Step 405′: The target eNB configures a new uplink and/or downlinkcomponent carrier or component carrier pair for the UE to use when theUE executes the random access.

Step 406: The target eNB sends the handover request acknowledgementmessage to the source eNB, where the handover request acknowledgementmessage includes information about the component carrier or thecomponent carrier pair configured by the target eNB for the UE to usewhen the UE executes the random access to the target eNB.

Furthermore, the target eNB may further include bandwidths of the uplinkand/or downlink component carriers or the component carrier pairsselected for the UE to use when the UE executes the random access to thetarget eNB, where the bandwidths are included in the handover requestacknowledgement message.

Step 407: After receiving the handover request acknowledgement message,the source eNB sends a handover command message to the UE.

If the target eNB accepts the uplink and/or downlink component carriersor component carrier pairs selected by the source eNB for the UE to usewhen the UE executes the random access to the target eNB, the handovercommand includes the information about the uplink and/or downlinkcomponent carriers or component carrier pairs selected by the source eNBfor the UE to use when the UE executes the random access to the targeteNB. Furthermore, the handover command may further include bandwidthinformation of the selected uplink and/or downlink component carriers orcomponent carrier pairs.

If the target eNB cannot allow the source eNB to select all or a part ofthe uplink and/or downlink component carriers or component carrier pairsfor the UE to use when the UE executes the random access to the targeteNB, the handover command includes the information about the uplinkand/or downlink component carriers or component carrier pairs determinedby the source eNB for the UE to use when the UE executes the randomaccess to the target eNB. Furthermore, the handover command may furtherinclude the bandwidth information of the selected uplink and/or downlinkcomponent carriers or component carrier pairs used to execute the randomaccess to the target eNB.

Step 408: After receiving the handover command, the UE sends a randomaccess preamble to the target eNB, where the handover command includesthe information about the uplink and/or downlink component carriers orthe component carrier pairs selected for the UE. Furthermore, thehandover command may further include the bandwidth information of theselected uplink and/or downlink component carriers or component carrierpairs.

That is, after receiving the handover command, the UE executes a processfor synchronizing with a target cell to access the target cell. The UEmonitors the downlink component carriers or the component carrier pairsaccording to the information about the allocated uplink and/or downlinkcomponent carriers or the component carrier pairs used to execute therandom access to the target eNB, where the information is in thehandover command. The UE sends the random access preamble to the targeteNB.

Step 409: After receiving the preamble sent by the UE, the target eNBsends a random access response message to the UE on the downlinkcomponent carrier selected for the UE to use when the UE executes therandom access.

The handover response message may include information about uplinkand/or downlink component carriers or component carrier pairs capable ofbeing newly allocated by the target eNB to the UE.

Step 410: When the UE accesses the target cell successfully, the UEsends a handover acknowledgement message to the target eNB.

Step 411: After receiving the handover acknowledgement message sent bythe UE, the target eNB allocates new uplink and/or downlink componentcarriers or component carrier pairs to the UE.

Here, the information about the uplink and/or downlink componentcarriers or the component carrier pairs newly allocated to the UE may besent to the UE in a form of a Medium Access Control (MAC) Protocol DataUnit (PDU), or a physical layer control channel (PCCH) or Radio ResourceControl (RRC) message, or other messages, which is not limited by theembodiment of the present invention.

Step 412: After receiving the information about the newly allocateduplink and/or downlink component carriers or component carrier pairs,the UE monitors the new uplink and/or downlink component carriers orcomponent carrier pairs.

Embodiments of the present invention further provide exemplaryEmbodiment 3. An implementation process in this embodiment is similar tothat in FIG. 3A and FIG. 3B or FIG. 4A and FIG. 4B. Differences lie instep 302 to step 304 in FIG. 3A and FIG. 3B or step 402 to step 404 inFIG. 4A and FIG. 4B, which are modified respectively as follows.

Step 302 (or step 402): The source eNB makes a handover decision toselect a target eNB and a target cell for the UE.

Step 303 (or step 403): The source eNB sends a handover request messageto the target eNB, where the handover request message includes the UE'scapability information about the supported component carriers.

Step 304 (or step 404): After receiving the handover request message,the target eNB executes admission control. If the target eNB allows theUE to access the target eNB, the target eNB configures new uplink and/ordownlink target component carriers or target component carrier pairs forthe UE.

Step 305 (or step 405): After receiving the handover request message,the target eNB executes the admission control. If the target eNB allowsthe UE to access the target eNB, the target eNB configures an uplinkand/or a downlink component carrier or a component carrier pair for theUE to use when the UE executes random access.

That is, in this embodiment, after the target eNB receives the handoverrequest message, if the target eNB allows the UE to access the targeteNB, the target eNB configures the new uplink and/or downlink targetcomponent carriers or target component carrier pairs for the UE, or thetarget eNB configures the uplink and/or downlink component carrier orcomponent carrier pair used to execute the random access for the UE; andthen the target eNB sends a configuration result to the source eNBthrough a handover request acknowledgement message. Subsequent executionsteps, that is, step 307 to step 309 are the same as those in FIG. 3Aand FIG. 3B or step 407 to step 412 are the same as those in FIG. 4A andFIG. 4B. For details, reference may be made to the foregoingdescription, and the details will not be described herein again.

In this embodiment, the information about the target component carriersspecifically includes frequency information, an identifier, or asequence number of the uplink and/or downlink component carrier or thecomponent carrier pair selected by the source eNB for the UE to use whenthe UE executes the random access, or frequency information, anidentifier, or a sequence number of the uplink and/or downlink componentcarrier or the target component carrier pair used to execute the randomaccess.

That is, if the handover request message includes the UE's capabilityinformation about the target component carriers being supported, thetarget eNB configures the target component carriers to which the UE isto be handed over according to the handover request message; and thenthe target eNB sends a handover request acknowledgement message to thesource eNB, where the handover request acknowledgement message includesthe information about the target component carriers configured, to whichthe UE is to be handed over.

Other implementation processes in this embodiment are similar to thecorresponding processes in the foregoing embodiment and will not bedescribed herein again.

In Embodiment 1 to Embodiment 3, the UE may need to be handed overbetween the component carriers in the communication process before andafter cell handover. Specifically, the handover of the UE between thecomponent carriers at the source eNB or at a new serving eNB (a targeteNB before the handover is completed) is described in the followingembodiment. Particularly, in Embodiment 2, when the target eNB allocatesthe new uplink and/or downlink component carriers or component carrierpairs for the UE after receiving the handover acknowledgement messagesent by the UE, and when the UE and the target eNB transmit data on thenewly allocated uplink and/or downlink component carriers or thecomponent carrier pairs, if the target eNB can re-allocate new uplinkand/or downlink component carriers or component carrier pairs for the UEaccording to needs (for example, the allocated component carriers areinsufficient or redundant or a better component carrier exists, but theembodiment is not limited thereto). Based on the foregoing embodiment,the method may further include the following steps.

The target eNB sends a component carrier handover command to the UE,where the component carrier handover command includes information aboutcomponent carriers or component carrier pairs re-selected, to which theUE is to be handed over.

After handover, the target eNB and the UE transmit the data on thecomponent carriers or the component carrier pairs. In the subsequenttransmission process, the target eNB may perform component carrierhandover according to needs. A specific implementation process may beimplemented through any embodiment in FIG. 5 to FIG. 7.

In the embodiment of the present invention, the handover acknowledgementmessage is further referred to as an RRC (Radio Resource Control)connection reconfiguration complete message.

Accordingly, an embodiment of the present invention further provides acomponent carrier handover method. FIG. 5 is a flow chart of thecomponent carrier handover method. The method includes the followingsteps.

Step 501: Receive a component carrier handover command sent by a servingeNB, where the component carrier handover command includes informationabout component carriers or component carrier pairs to which the UE isto be handed over.

The serving eNB may be a source eNB of the UE before cell handover isperformed or may be an eNB of the UE after the cell handover isperformed, that is, a target eNB during the handover.

Step 502: The UE is handed over to the component carriers or thecomponent carrier pairs.

Step 503: Transmit data on the component carriers or the componentcarrier pairs after handover.

The method may further include receiving a new timing advance command ornew timing advance information sent by the serving eNB when receivingthe component carrier handover command sent by the serving eNB.

The transmitting the data on the component carriers or the componentcarrier pairs after handover further includes transmitting, through thenew timing advance command or the new timing advance information, thedata on the component carriers or the component carrier pairs afterhandover.

The information about the component carriers or the component carrierpairs includes: frequency information, identifiers, or sequence numberinformation of the component carriers or the component carrier pairs.

The method may further include: sending a component carrier handoveracknowledgement message to the serving eNB.

The component carrier handover command further includes a handoverstarting time of the component carrier or the component carrier pair.

In this embodiment, the component carriers specifically include anuplink component carrier and a downlink component carrier, and thecomponent carrier pair specifically includes an uplink/ a downlinkcomponent carrier pair.

In a handover process of the component carrier handover, in uplinkcomponent carrier handover, data not yet transmitted successfully on anoriginal uplink component carrier before the handover is transmitted tothe serving eNB on a new component carrier after the handover or on acomponent carrier that does not undergo the handover; in downlinkcomponent carrier handover, data not yet transmitted successfully on anoriginal downlink component carrier before the handover is transmittedto the UE on a new component carrier after the handover or on acomponent carrier that does not undergo the handover; and inuplink/downlink component carrier pair handover, data not yettransmitted successfully on an original uplink/downlink componentcarrier pairs before the handover is transmitted to the UE or theserving eNB on a new component carrier pair after the handover or on acomponent carrier pair that does not undergo the handover.

The component carrier handover command may adopt an MAC layer message, aphysical layer message, or an RRC layer message.

In this embodiment, the component carrier handover command sent by theserving eNB is received to re-select the component carrier or thecomponent carrier pair to which the UE is to be handed over, so that theterminal may receive a random access response message on the re-selectedcomponent carrier or component carrier pair.

Accordingly, an embodiment of the present invention further provides acomponent carrier handover method. FIG. 6 is a flow chart of thecomponent carrier handover method. The method includes the followingsteps.

Step 601: Send a component carrier handover command to a UE, where thecomponent carrier handover command includes information about componentcarriers or component carrier pairs to which the UE is to be handedover.

Step 602: Transmit data on the component carriers or the componentcarrier pairs in the component carrier handover command.

The method further includes receiving a component carrier handoveracknowledgement message sent by the UE.

In this embodiment, the component carrier handover command is sent tothe UE, so that the UE may transmit the data on the re-selectedcomponent carriers or component carrier pair and implement a randomaccess procedure.

For specific implementation processes in FIG. 5 and FIG. 6, referencemay be made to FIG. 7.

FIG. 7 is a specific flow chart of a component carrier handover methodaccording to Embodiment 4 of the present invention. Referring to FIG. 7,the method includes the following steps.

Step 701: A serving eNB sends a component carrier handover command to aUE, where the component carrier handover command includes informationabout uplink component carriers or downlink component carriers oruplink/downlink component carrier pairs to which the UE is to be handedover, and the information may be frequency information, identifiers, orsequence number information of the component carriers or the componentcarrier pairs.

The component carrier handover command may be in the form of an MAClayer message, a physical layer message, or an RRC message. For example,an Information Element (IE) or an MAC PDU may be added in an RRCconnection configuration message. Moreover, a PCCH may further beadopted to instruct the UE to perform rapid component carrier handover.That is, an eNB may employ a Physical Downlink Control Channel (PDCCH)(that is, the PDCCH includes the information about the uplink componentcarriers or the downlink component carriers or the uplink/downlinkcomponent carrier pairs to which the UE is to be handed over) to notifythe UE of the target component carriers to which the UE is to be handedover. Moreover, the component carrier handover command shall includeinformation about starting time of the handover for the componentcarrier or the component carrier pair, that is, a handover starting timeof the component carrier or the component carrier pair, to ensuresynchronization between the UE and the eNB.

Optionally, the eNB may further send a Timing Advance Command MACcontrol element or timing advance information to the UE at the time ofsending the component carrier handover command, or send the componentcarrier handover command carrying the timing advance information to theUE, which is not limited by the embodiment of the present invention.

Step 702: After the handover succeeds, the UE sends component carrieracknowledgement information to the eNB to indicate agreeing to be handedover to the indicated component carriers to work. This step is optional.

Step 703: After receiving the component carrier handover command sent bya serving eNB, the component carriers used by the UE is handed over tothe indicated component carriers or component carrier pairs.

Step 704: The UE and the serving eNB transmit (that is, send andreceive) data on the component carriers after handover. Specifically,when receiving the timing advance information sent by the eNB, the UEadopts the new timing advance information when sending or receiving thedata on the component carriers.

Optionally, before the handover moment of the component carriers or thecomponent carrier pair arrives, the UE may further send componentcarrier acknowledgement information to the eNB to indicate agreeing tobe handed over to the indicated component carriers or component carrierpair to work.

In the handover process in this embodiment, user plane data processingincludes the following three situations.

(1) In downlink component carrier handover, data not yet transmittedsuccessfully to the UE (including data not yet transmitted by the eNB tothe UE and data not yet correctly received and acknowledged by the UEbefore handover) on a replaced serving component carrier (that is, anoriginal serving component carrier) during the handover is transmittedor retransmitted to the UE on a component carrier that does not undergothe handover or on a new component carrier after the handover.

(2) In uplink component carrier handover, data not yet transmittedsuccessfully to the eNB (including data not yet transmitted by the UE tothe eNB and data not correctly received and acknowledged by the eNBbefore handover) on a replaced serving component carrier during thehandover is transmitted or retransmitted to the eNB on a componentcarrier that does not undergo the handover or on a new component carrierafter the handover.

(3) In uplink and downlink component carriers/component carrier pairhandover, data not yet transmitted successfully (data not yettransmitted by the UE to the eNB and data not correctly received andacknowledged by the eNB before handover and data not transmitted by theeNB to the UE and data not correctly received and acknowledged by the UEbefore handover) on replaced serving component carriers/a componentcarrier pair during the handover is transmitted or retransmitted on thecomponent carrier that does not undergo the handover or on the newcomponent carrier after the handover.

Based on the implementation process of the foregoing method, anembodiment of the present invention further provides an eNB. FIG. 8 is aschematic structure diagram of the eNB. The eNB includes a determinationunit 81, a notification unit 82, and a sending unit 83. Thedetermination unit 81 is adapted to determine information of the targetcomponent carriers to which the UE is to be handed over. Thenotification unit 82 is adapted to notify the UE of the informationabout the target component carriers through a source eNB. The sendingunit 83 is adapted to send a random access response message on at leastone component carrier in the target component carriers after a dedicatedrandom access preamble sent by the UE is received.

The determination unit includes a message receiving unit and a componentcarrier determination unit. The message receiving unit is adapted toreceive a handover request message sent by the source eNB. The componentcarrier determination unit is adapted to determine, according to thehandover request message, the target component carriers to which the UEis to be handed over, after the message receiving unit receives thehandover request message. The notification unit 82 is specificallyadapted to notify, through a handover request acknowledgement message,the source eNB of the information about the target component carriersdetermined by the component carrier determination unit after thecomponent carrier determination unit determines the target componentcarriers to which the UE is to be handed over, so that the source eNBsends the target component carriers to the UE through a handovercommand.

A specific implementation process is as follows.

The message receiving unit receives the handover request message sent bythe source eNB, where the handover request message includes the UE'scapability information about the target component carriers beingsupported; the component carrier determination unit configures,according to the handover request message, the target component carriersto which the UE is to be handed over; and the notification unit sendsthe handover request acknowledgement message to the source eNB after thecomponent carrier determination unit determines the information aboutthe target component carriers to which the UE is to be handed over,where the handover request acknowledgement message includes informationabout the target component carriers configured, to which the UE is to behanded over. After the handover request acknowledgement message is sent,the message receiving unit instructs the sending unit to send the randomaccess response message on at least one component carrier in the targetcomponent carriers after receiving the dedicated random access preamblesent by the UE.

Another specific implementation process is as follows. The determinationunit may further include a massage receiving unit, a judgment unit, anda component carrier determination unit.

The massage receiving unit receives a handover request message sent bythe source eNB, where the handover request message includes the UE'scapability information about the target component carriers beingsupported and information about the target component carriers selectedby the source eNB, and the target component carriers are the carriers towhich the UE is to be handed over.

The judgment unit determines, according to the handover request messagereceived by the massage receiving unit, whether to allow the source eNBto select the target component carriers to which the UE is to be handedover, and sends a determination result, that is, sends an allowancedetermination result to the notification unit directly and sends anon-allowance determination result to the component carrierdetermination unit.

When receiving the allowance determination result, the notification unitsends a handover request acknowledgement message to the source eNB,where the handover request acknowledgement message includesacknowledgement information of the target component carriers selected bythe source eNB, or the information about the target component carriersselected by the source eNB, and the target component carriers are thecarriers to which the UE is to be handed over.

When receiving the non-allowance determination result, the componentcarrier determination unit configures, according to the UE's capabilityinformation about the target component carriers being supported, thetarget component carriers to which the UE is to be handed over, andsends a handover request acknowledgement message to the source eNB,where the handover request acknowledgement message includes informationabout the target component carriers configured, to which the UE is to behanded over. After the handover request acknowledgement message is sent,the message receiving unit instructs the sending unit to send the randomaccess response message on at least one component carrier in the targetcomponent carriers after receiving the dedicated random access preamblesent by the UE.

In this embodiment, after sending the random access response message,the method further includes: after receiving the handoveracknowledgement message sent by the UE, allocating new uplink and/ordownlink component carriers or new component carrier pairs to the UE.

It should be noted that, in the embodiment of the present invention, theinformation of the target component carriers may include, but are notlimited to, uplink and/or downlink target component carriers or targetcomponent carrier pairs selected by the source eNB for the UE; or anuplink and/or a downlink component carrier or a component carrier pairused to execute random access; or frequency information, identifiers orsequence numbers of the uplink and/or downlink target component carriersor the target component carrier pairs, or frequency information, anidentifier or a sequence number of the uplink and/or downlink componentcarrier or the target component carrier pair used to execute the randomaccess.

For details of an implementation process of functions and effects ofunits in the eNB, reference may be made to the implementation process ofthe foregoing method, and the details will not be described hereinagain.

Accordingly, an embodiment of the present invention further provides aterminal equipment. FIG. 9 is a schematic structure diagram of theterminal equipment. The terminal equipment includes: a handover commandreceiving unit 91, a sending unit 92, and a random response receivingunit 93. The handover command receiving unit 91 is adapted to receive ahandover command sent by a source eNB, where the handover commandincludes information about target component carriers configured by atarget eNB, or information about target component carriers selected bythe source eNB, and the target component carriers are the carriers towhich the UE is to be handed over. The sending unit 92 is adapted tosend a dedicated random access preamble to the target eNB after thehandover command receiving unit receives the handover command. Therandom response receiving unit 93 is adapted to receive a random accessresponse message on a downlink target carrier in the target componentcarriers configured for the UE or a downlink component carrier in thetarget component carriers selected by the source eNB, and the targetcomponent carriers are the carriers to which the UE is to be handedover, after the sending unit sends the dedicated random access preamble.

After the random response receiving unit receives the random accessresponse message, the terminal equipment may further include a componentcarrier receiving unit.

The component carrier receiving unit is adapted to receive new uplinkand/or downlink target component carriers or new uplink and/or downlinktarget component carrier pairs allocated by the target eNB for the UE,after a handover acknowledgement message is sent to the target eNB.

The terminal equipment further includes a monitoring unit, adapted tomonitor the target component carriers selected by the source eNB,and thetarget component carriers are the carriers to which the UE is to behanded over, or adapted to monitor the target component carriersconfigured, according to the UE's capability information about thesupported component carriers, by the target eNB, and the targetcomponent carriers are the carriers to which the UE is to be handedover, which are indicated in the handover command, after the handovercommand receiving unit receives the handover command.

For details of an implementation process of functions and effects ofunits in the eNB, reference may be made to the implementation process ofthe foregoing method, and the details will not be described hereinagain.

Accordingly, an embodiment of the present invention further provides aterminal equipment. FIG. 10 is a schematic structure diagram of theterminal equipment. The terminal equipment includes: a receiving unit1001, a handover unit 1002, and a transmission unit 1003. The receivingunit 1001 is adapted to receive a component carrier handover commandsent by a serving eNB, where the component carrier handover commandincludes information about component carriers or component carrier pairsto which the UE is to be handed over. The handover unit 1002 is adaptedto hand over the UE to the component carriers or the component carrierpairs, after the receiving unit 1001 receives the handover command. Thetransmission unit 1003 is adapted to transmit data on the componentcarriers or the component carrier pairs after handover, after thehandover unit 1002 successfully performs the handover.

The receiving unit 1001 is further adapted to receive a new timingadvance command or new timing advance information sent by the servingeNB when receiving the component carrier handover command. Thetransmission unit 1003 is further adapted to transmit, through the newtiming advance command or the new timing advance information, the dataon the component carriers or the component carrier pairs after handover.

The terminal equipment further includes a sending unit, adapted to senda component carrier handover acknowledgement message to the serving eNBafter the handover unit successfully performs the handover.

For details of an implementation process of functions and effects ofunits in the terminal equipment, reference may be made to theimplementation process of the foregoing method, and the details will notbe described herein again.

Accordingly, an embodiment of the present invention further provides aneNB. FIG. 11 is a schematic structure diagram of the eNB. The eNBincludes a handover command sending unit 111 and a data transmissionunit 112. The handover command sending unit 111 is adapted to send acomponent carrier handover command to a UE, where the handover commandincludes information about component carriers or component carrier pairsto which the UE is to be handed over. The data transmission unit 112 isadapted to transmit data on the component carriers or the componentcarrier pairs after the handover command sending unit 111 sends thehandover command.

The eNB further includes a receiving unit, adapted to receive acomponent carrier handover acknowledgement message sent by the UE, afterthe handover command sending unit sends the handover command.

For details of an implementation process of functions and effects ofunits in the eNB, reference may be made to the implementation process ofthe foregoing method, and the details will not be described hereinagain.

It can be seen that, in the embodiment of the present invention, whenthe source eNB decides to perform the handover, the source eNB sends thehandover request message to the target eNB, where the handover requestmessage includes: the UE's capability information about the targetcomponent carriers being supported, or the UE's capability informationabout the target component carriers being supported and the informationabout the target component carriers selected by the source eNB, and thetarget component carriers are the carriers to which the UE is to behanded over. After the target eNB receives the handover request, twosituations occur. One is that the target eNB agrees with the informationabout the target component carriers selected by the source eNB, and thetarget component carriers are the carriers to which the UE is to behanded over, and sends a handover request acknowledgement messageindicating agreement to the source eNB; the other is that: afterreceiving the handover request, the target eNB configures, according tothe UE's capability information about the target component carriersbeing supported, the target component carriers, to which the UE is to behanded over, and sends the configuration result to the source eNBthrough the handover request acknowledgement message. After receivingthe handover request acknowledgement message, the source eNB sends thehandover command to the UE, where the handover command includes thetarget component carriers configured by the target eNB, or the targetcomponent carriers selected by the source eNB, and the target componentcarriers are the carriers to which the UE is to be handed over. Afterreceiving the handover command, the UE monitors the target componentcarriers in the handover command, and after sending the dedicated randomaccess preamble to the target eNB, receives the random access responsemessage on at least one target component carrier in the target componentcarriers which are monitored. Similarly, after receiving the dedicatedrandom access preamble sent by the UE, the target eNB sends the randomaccess response message on at least one component carrier in the targetcomponent carriers. It can be seen that: after receiving the handovercommand, the UE learns the component carriers that are used for thetarget eNB to send the random access response message, so as to receivethe random access response message on the component carriers, therebyreducing power consumption of the UE; and meanwhile, after receiving thededicated random access preamble, the target eNB learns the componentcarriers that are used for sending the random access response message,thereby increasing utilization rate of downlink resources. Similarly,after receiving the handover command, the UE learns the informationabout the component carriers or the component carrier pairs, to whichthe UE is to be handed over, is handed over to the component carriers orthe component carrier pairs, and transmits the data on the componentcarriers or the component carrier pairs after handover, thereby reducingthe power consumption of the UE, and meanwhile, the serving eNBtransmits the data on the component carriers or the component carrierpairs after sending the handover command, thereby increasing theutilization rate of downlink resources.

Through the above description of the implementation, persons skilled inthe art may clearly understand that the present invention may beimplemented through software plus a necessary universal hardwareplatform, and definitely may also be implemented through hardware. Butin many cases, the former is preferred. Based on this understanding, thetechnical solutions or the part that makes contributions to the priorart may be substantially embodied in the form of a software product. Thecomputer software product may be stored in a storage medium such as aRead Only memory (ROM)/Random Access Memory (RAM), a magnetic disk, oran optical disk, and contain several instructions to instruct computerequipment (for example, a personal computer, a server, or networkequipment) to perform the methods described in the embodiments of thepresent invention or in some parts of the embodiments of the presentinvention.

The above descriptions are merely exemplary embodiments of the presentinvention. It should be noted that persons of ordinary skill in the artmay make modifications and improvements without departing from theprinciple of the present invention, which should be construed as fallingwithin the protection scope of the present invention.

1. A random access method, comprising: determining at least one targetcomponent carrier to which a User Equipment (UE) is to be handed over,and notifying the UE of information about the at least one targetcomponent carrier through a source evolved Node B (eNB); and afterreceiving a dedicated random access preamble sent by the UE, sending arandom access response message on at least one component carrier in theat least one target component carrier.
 2. The method according to claim1, wherein determining the at least one target component carrier andnotifying the UE of the information about the at least one targetcomponent carrier through the source eNB comprises: determining the atleast one target component carrier according to a handover requestmessage after receiving the handover request message sent by the sourceeNB; notifying the source eNB of the information about the at least onetarget component carrier through a handover request acknowledgementmessage; and sending, by the source eNB, the at least one targetcomponent carrier to the UE through a handover command.
 3. The methodaccording to claim 2, wherein determining the at least one targetcomponent carrier according to the handover request message afterreceiving the handover request message sent by the source eNB comprises:receiving the handover request message sent by the source eNB, whereinthe handover request message comprises the UE's capability informationabout the at least one target component carrier being supported; andconfiguring the at least one target component carrier according to thehandover request message; and notifying the source eNB of theinformation about the at least one target component carrier through thehandover request acknowledgement message comprises: sending the handoverrequest acknowledgement message to the source eNB, wherein the handoverrequest acknowledgement message comprises the information about the atleast one target component carrier configured.
 4. The method accordingto claim 2, wherein determining the at least one target componentcarrier according to the handover request message, after receiving thehandover request message sent by the source eNB comprises: receiving thehandover request message sent by the source eNB, wherein the handoverrequest message comprises the UE's capability information about the atleast one target component carrier being supported and information of atarget component carrier selected by the source eNB, and the targetcomponent carrier selected is a carrier to which the UE is to be handedover; and determining whether to allow the source eNB to select the atleast one target component carrier; if the source eNB is allowed toselect the at least one target component carrier, the notifying thesource eNB of the information about the at least one target componentcarrier through the handover request acknowledgement message comprises:sending the handover request acknowledgement message to the source eNB,wherein the handover request acknowledgement message comprisesacknowledgement information of the target component carrier selected bythe source eNB, or the information about the target component carrierselected by the source eNB; and if the source eNB is not allowed toselect the at least one target component carrier, configuring the atleast one target component carrier and the notifying the source eNB ofthe information about the at least one target component carrier throughthe handover request acknowledgement message comprises: sending thehandover request acknowledgement message to the source eNB, wherein thehandover request acknowledgement message comprises the information aboutthe at least one target component carrier configured.
 5. The methodaccording to claim 4, wherein after the sending the random accessresponse message, the method further comprises: after receiving ahandover acknowledgement message sent by the UE, allocating at least oneof the following elements to the UE: a new uplink component carrier, anew downlink component carrier and a new component carrier pair.
 6. Themethod according to claim 5, wherein when a target eNB is required tore-allocate at least one of the following elements for the UE: a newuplink component carrier, a new downlink component carrier and a newcomponent carrier pair, the method further comprises: sending acomponent carrier handover command to the UE, wherein the componentcarrier handover command comprises information about the at least one ofthe elements re-allocated; and transmitting data on the at least one ofthe elements re-allocated after handover.
 7. The method according toclaim 3, wherein sending, by the source eNB, the at least one targetcomponent carrier to the UE through the handover command comprises:after receiving a handover acknowledgement message sent by a target eNB,sending, by the source eNB, the handover command to the UE, wherein thehandover command comprises: the information about the at least onetarget component carrier configured by the target eNB or selected by thesource eNB.
 8. The method according to claim 7, wherein handover requestacknowledgement message further comprises a bandwidth of the at leastone target component carrier configured by the target eNB; and thehandover command further comprises the bandwidth of the at least onetarget component carrier configured by the target eNB, or a bandwidth ofthe at least one target component carrier selected by the source eNB. 9.The method according to claim 1, wherein the at least one targetcomponent carrier comprises at least one of: a uplink target componentcarrier, a downlink target component carrier and a target componentcarrier pair selected for the UE or used to execute random access; andthe information about the at least one target component carriercomprises: frequency information, an identifier, or a sequence number ofthe at least one of: the uplink component carrier, the downlink targetcomponent carrier and the target component carrier pair selected for theUE or used to execute the random access.
 10. A random access method,comprising: receiving a handover command sent by a source evolved Node B(eNB), wherein the handover command comprises information about at leastone target component carrier configured by a target eNB or selected bythe source eNB, and the at least one target component carrier is acarrier to which a User Equipment (UE) is to be handed over; and aftersending a dedicated random access preamble to the target eNB, receivinga random access response message on at least one downlink target carrierin the at least one target component carrier.
 11. The method accordingto claim 10, wherein after the receiving the random access responsemessage, the method further comprises: sending a handoveracknowledgement message to the target eNB, and receiving at least one ofthe following elements: a new uplink target component carrier, a newdownlink target component carrier, a new uplink target component carrierpair and a new downlink target component carrier pair allocated by thetarget eNB for the UE.
 12. The method according to claim 11, furthercomprising: receiving a component carrier handover command sent by thetarget eNB, wherein the component carrier handover command comprisesinformation about a component carrier or a component carrier pairre-selected, and the component carrier or the component carrier pairre-selected is a carrier or a carrier pair to which the UE is to behanded over; handing over the UE to the component carrier or thecomponent carrier pair re-selected; and transmitting data on thecomponent carrier or the component carrier pair re-selected afterhandover.
 13. The method according to claim 12, further comprising: whenreceiving the component carrier handover command sent by the target eNB,receiving a new timing advance command or new timing advance informationsent by the target eNB, wherein transmitting the data on the componentcarrier or the component carrier pair re-selected after handover furthercomprises: transmitting the data on the component carrier or thecomponent carrier pair re-selected after handover through the new timingadvance command or the new timing advance information; and the componentcarrier handover command further comprises a handover starting time ofthe component carrier or the component carrier pair re-selected.
 14. Anevolved Node B (eNB), comprising: a determination unit, configured todetermine at least one target component carrier to which a UserEquipment (UE) is to be handed over; a notification unit, configured tonotify the UE of information about the at least one target componentcarrier through a source eNB; and a sending unit, configured to send arandom access response message on at least one component carrier in theat least one target component carrier after a dedicated random accesspreamble sent by the UE is received.
 15. The eNB according to claim 14,wherein the determination unit comprises: a message receiving unit,configured to receive a handover request message sent by the source eNB;and a component carrier determination unit, configured to determine,according to the handover request message, the at least one targetcomponent carrier after the message receiving unit receives the handoverrequest message.
 16. The eNB according to claim 14, wherein thenotification unit is further configured to notify the source eNB of theinformation about the at least one target component carrier through ahandover request acknowledgement message, wherein the source eNB is usedto send the at least one target component carrier to the UE through ahandover command.
 17. The eNB according to claim 14, wherein the messagereceiving unit is configured to receive the handover request messagesent by the source eNB, wherein the handover request message includesthe UE's capability information about the at least one target componentcarrier being supported.
 18. A terminal equipment, comprising: ahandover command receiving unit, configured to receive a handovercommand sent by a source evolved Node B (eNB), wherein the handovercommand comprises information about at least one target componentcarrier configured by a target eNB or selected by the source eNB, andthe at least one target component carrier is a carrier to which a UserEquipment (UE) is to be handed over; a sending unit, configured to senda dedicated random access preamble to the target eNB after the handovercommand receiving unit receives the handover command; and a randomresponse receiving unit, configured to receive a random access responsemessage on at least one downlink component carrier in the at least onetarget component carrier after the sending unit sends the dedicatedrandom access preamble.
 19. The terminal equipment according to claim18, further comprising: a monitoring unit, configured to monitor the atleast one target component carrier, after the handover command receivingunit receives the handover command.
 20. The terminal equipment accordingto claim 18, further comprising: a component carrier receiving unit,configured to receive at least one of: a new uplink target componentcarrier, a new downlink target component carrier, a new uplink targetcomponent carrier pair and a new downlink target component carrier pairallocated by the target eNB, after a handover acknowledgement message issent to the target eNB.